Boston starter Josh Beckett delivers a pitch in the first inning. Beckett earned his 100th career victory in a 6-0 Red Sox victory over the Royals on Sunday in Boston.

Boston ? Josh Beckett’s 100th career victory may have been his best.

The Red Sox ace capped a brilliant first half of the season with a three-hitter, joining teammate Tim Wakefield as the only 11-game winners in the AL as the Boston Red Sox beat the Kansas City Royals, 6-0, Sunday.

“It’s pretty memorable” to post his 100th win, Beckett said, “and the way I did it is cool.”

Beckett (11-3) retired the first nine batters, five on strikeouts. It was his second shutout and complete game of the season following his 3-0 victory over Atlanta on June 20. He finished with seven strikeouts and no walks.

In seven career complete games, his 94 pitches Sunday tied that Braves game for the fewest and the three hits were the fewest he allowed.

“Oh, he was good,” Boston manager Terry Francona said. “He attacked the strike zone with his fastball and it was very obvious they wanted to hit his fastball.”

They couldn’t.

“Not a lot we could do with him,” Kansas City manager Trey Hillman said.

It was a fitting end to a stretch in which Beckett went 9-1 with a 2.14 earned-run average after struggling at 2-2 with a 7.22 ERA through April.

Beckett allowed a ground-ball double down the right-field line to David DeJesus leading off the fourth and singles by Mitch Maier and Mark Teahen in the seventh.

“Believe it or not, he had to battle in the middle innings,” Red Sox catcher Jason Varitek said. “It don’t think it comes that easy for him as people may think. He falls off it as much as anybody and has to make adjustments during games.

“He’s pretty much a bulldog.”

Rookie Aaron Bates, called up last Monday, went 3-for-4 with two doubles and an RBI, and stabbed a line drive by Brayan Pena for the second out of the fifth. Bates could be sent down after the All-Star break with Mike Lowell possibly coming off the disabled list.

“I want to learn as much as I can in the short amount of time I’m here, and if you can help them win some games that’s obviously the main goal,” Bates said.

Bruce Chen (0-4) and four Royals relievers walked nine batters. Chen came out after allowing the first two batters in the fourth to reach base.

“Lots of balls in the air and too dangerous to leave him in and have any chance at all,” Hillman said.

Boston scored a run in the first on Kevin Youkilis’ RBI single and three in the fourth when Bates bashed a run-scoring double, David Ortiz grounded out for another RBI and Jason Varitek walked with the bases loaded.

The fifth run came across in the fifth when Nick Green, who had walked and taken third on a single by Bates, scored on Jacoby Ellsbury’s double-play grounder. Rocco Baldelli doubled in the final run in the eighth.

Beckett and Wakefield, also 11-3, will represent the Red Sox along with closer Jonathan Papelbon, left fielder Jason Bay and Youkilis in the All-Star game Tuesday in St. Louis. AL starting second baseman Dustin Pedroia withdrew Sunday to be with his wife, who has had complications with her pregnancy.

Beckett allowed two runs or less for the ninth time in 11 starts and is 6-0 in nine home starts this year.

He began the game by striking out DeJesus and Maier and retiring Billy Butler on a fly to left. He started the second with two more strikeouts

The Red Sox won four of their last five games to improve to 54-34, their fifth-best record at the All-Star break since 1954. They’ve held at least a share of first place in the AL East since June 9. Kansas City lost for the fourth time in five games — including a 1-0 loss to Boston on Friday — and fell 14 games below .500.